Clean-up of the system shutdown code paths

chrome/browser/ui/ash/system_tray_delegate_chromeos.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/ui/ash/system_tray_delegate_chromeos.h"
 
 #include <algorithm>
 #include <set>
 #include <string>
 #include <vector>
@@ skipping 578 matching lines @@
     if (show_intro) {
       base::Callback<void(bool)> on_accept =
           base::Bind(&OnAcceptMultiprofilesIntro);
       ShowMultiprofilesIntroDialog(on_accept);
     } else {
       UserAddingScreen::Get()->Start();
     }
   }
 }
 
-void SystemTrayDelegateChromeOS::ShutDown() {
-  ash::Shell::GetInstance()->lock_state_controller()->RequestShutdown(
-      ash::LockStateController::POWER_OFF);
-}
-
 void SystemTrayDelegateChromeOS::SignOut() {
   chrome::AttemptUserExit();
 }
 
 void SystemTrayDelegateChromeOS::RequestLockScreen() {
   // TODO(antrim) : additional logging for crbug/173178
   LOG(WARNING) << "Requesting screen lock from AshSystemTrayDelegate";
   DBusThreadManager::Get()->GetSessionManagerClient()->RequestLockScreen();
 }
 
@@ skipping 743 matching lines @@
   LOG(WARNING) << "SystemTrayDelegateChromeOS::GetChildUserMessage call while "
                << "ENABLE_SUPERVISED_USERS undefined.";
   return base::string16();
 }
 
 ash::SystemTrayDelegate* CreateSystemTrayDelegate() {
   return new SystemTrayDelegateChromeOS();
 }
 
 }  // namespace chromeos